Broomfield has two main sources of water. Treated water is purchased from Denver Water, and raw water is supplied to the Water Treatment Plant by the Colorado-Big Thompson Project and Windy Gap system under the management of the Northern Colorado Water Conservancy District.

The Windy Gap Project consists of a diversion dam, a pumping facility, and a pipeline to Lake Granby. The CBT system includes a total of ten reservoirs, thirteen dams, six power plants, three pumping plants, and associated canals and waterways. The Alva B. Adams tunnel is a means of conveying this collected water 13.1 miles through the Continental Divide to the eastern slope. After leaving the tunnel, the water falls through six power plants and eventually into Carter Lake. A 32-mile water conveyance pipeline from Carter Lake to the Matthew D. Glasser Reservoir supplies the water used by the City’s treatment facility.